Piston ring

ABSTRACT

The present invention relates to piston machines and, more particularly, to piston rings. The piston ring 1 has blind slots 2 and slots 5 which form channels. The blind slots 2 open on the outer surface 3 and on the face surface 4. The slots 5 are made from inside of the ring 1 and form channels which open on the face surfaces 4 and 6 and on the outer surface 3. The spaces between the adjacent slots 2 and 5 form flexible bridges.

United States Patent [191 Prostorov et al.

[54] PISTON RING [76] Inventors: Igor Semenovich Prostorov, poselokKrivka, ulitsa Festivalnaya, 3, RV. 3, Leningradskaya oblast; VladimirSergeevich Davydov, prospekt Smirnova, 6, kv. 21, Leningrad, both ofUSSR.

[22] Filed: Mar. 14, 1972 21 Appl. No.: 234,522

[52] US. Cl ..277/2l5, 92/249 [51] Int. Cl. ..Fl6j 9/08 [58] Field ofSearch .277/2 14-222, 27;

[56] References Cited UNITED STATES PATENTS Godron ..277/2 1 5 [45] May29,1973

2,311,731 2/1943 Bowers ..277/2 1 5 FOREIGN PATENTS OR APPLICATIONS527,842 10/1940 Great Britain ..277/2l6 Primary ExaminerSamuel B.Rothberg Assistant Examiner-Robert I. Smith Attorney-Eric H. Waters,John G. Schwartz and J. Harold Nissen [57] ABSTRACT The presentinvention relates to piston machines and, more particularly, to pistonrings.

The piston ring 1 has blind slots 2 and slots 5 which form channels. Theblind slots 2 open on the outer surface 3 and on the face surface 4. Theslots 5 are made from inside of the ring 1 and form channels which openon the face surfaces 4 and 6 and on the outer surface 3. The spacesbetween the adjacent slots 2 and 5 form flexible bridges.

2 Claims, 4 Drawing Figures rrsron RING The present invention relates topiston machines and, more specifically, to piston rings. Theinventioncan find preferential employment as a piston seal, mostly in thebuilt-up pistons of high-pressure compressors.

Known in the art is an integral piston ring with slots arrangedalternately on its outer and cylindrical surfaces. The slots extendthrough the ring in the axial direction. Bending of the flexible bridgesbetween the adjacent slots compensates for the elongation andcompression of the circular fibres of the ring caused by the variationsof temperature.

However, to provide efficient sealing of, say, the cylinder of a pistoncompressor, two rings of such a type should be placed side by side sothat the through slots of one ring would be covered by the body of theother one.

An object of the present invention resides in improving the reliabilityof sealing.

Another object of the invention resides in improving the seal.

In accordance with these and other objects the invention consists inthat the piston ring has blind slots opening on its outer surface and onone of its face surfaces; between at least two blind slots there is aslot made from inside of the ring and forming a channel which opens oneach face and outer surface of the ring.

Such a design of the ring rules out the necessity for covering its slotsby another ring, improves the reliability and sealing capacity of thering.

According to one of the embodiments of the invention, the channel madefrom inside of the ring is covered by a circular insert.

The ring with a circular insert installed, say, in the cylinder of acompressor, functions as a throttling ring and is capable of beingself-centered in said cylinder by the flow of gas moving along the outersurface of the ring.

Other objects and advantages of the invention will become more apparentfrom the detailed description of the ring that follows, and from theaccompanying drawings, in which:

FIG. lis a diagrammatic view of the piston ring according to theinvention;

FIG. 2 is a section taken along line II-II in FIG. 11;

FIG. 3 is a section taken along line III-III in FIG. ll;

FIG. d is an axonometric view of the piston ring according to theinvention, with a circular insert.

The piston ring 1 (FIG.1I) made of a nonmetallic material, for example afluoroplastic-based material, has blind slots 2 which open on the outersurface 3 and on the face surfaced, and slots 5 made from inside of thering land located between two adjacent blind slots 2. Each slot 5 formsa channel which opens on the face surfaces 4, 6 and on the outer surface3. The slots 5 are pentagon-shaped (FIG.2) while the blind slots 2 havethe shape of a triangle (F103). The adjacent slots 2 and 5 are made sothat their counter-opposed recesses are mutually covered, formingflexible inclined bridges 8 (FIGA).

The piston ring functions as follows.

The piston ring 1 is installed without a clearance or with a minimumclearance on the cylindrical surface of the piston groove (not shown inthe drawings) which covers completely the slots 5 on the side of theinner surface 7 of the ring 1. Besides, being an element of thecomposite piston seal, the ring 1 is directed with its face surface 6towards the high-pressure side so that the face surface 4 proves to bedirected towards the lowpressure side. Acted upon by the pressuredifferential applied to the face surfaces 6 and 4, the ring is forcedoff towards the low-pressure side and is pressed against the facesurface of the piston groove (not shown in the drawings) so that theoutlets of the slots 5 at the lowpressure side prove to be completelycovered, thus ensuring the requisite sealing of, say, compressorcylinder at the side of the compression chamber.

If the piston ring 1 is installed in, say, a compressor cylinder (notshown in the drawings), the clearance between its outer surface 3 andthe inner surface of the cylinder (not shown in the drawings) is takento be a minimum one, just sufficient for ensuring the temperatureexpansion of the radial thickness of the ring 1. Before the machinereaches the preset temperature level, the ring 1 has a radial clearanceand functions as a throttling ring with the main gap along the outersurface 3. After the compressor stage has reached the rated temperature,the linear expansion of the ring 1 is made up for by bending of theflexible bridges 8 between the adjacent slots 2 and 5. The radialclearance between the inner surface of the cylinder (not shown in thedrawings) and the outer surface 3 of the ring ll becomes smaller.Therefore, the piston ring 1 starts functioning as a throttling ringwith the gaps of a smaller size.

Under the effect of the different pressures applied to the outer surface3 and the inner surface '7, the outer surface 3 of the ring can bepressed against the inner surface of the cylinder (not shown in thedrawings). In this case the piston ring functions as a self-sealingelement of the piston seal, ensuring a minimum leakage.

In case of a sharp temperature drop, for example, in the compressorcylinder (not shown in the drawings) the reduction of the outsidediameter of the ring 1 is likewise made up for by bending of theflexible bridges 8.

Second version of the piston ring (FIGA).

The piston ring 1 is installed without a clearance on the circularinsert 9 which covers completely the slots 5 from the inner surface 7 ofthe ring 1. Then the ring 1 with the circular insert 9 is installed intothe piston groove (not shown in the drawings) and, for example, into thecompressor cylinder (not shown in the drawings) with a minimum clearancebetween the outer surface 3 of the ring and the inner surface of thecylinder.

The .ring 1 installed on the circular insert 9 functions as follows.

The gas flowing along the outer surface 3 of the ring 1 aligns it in thecylinder (not shown in the drawings). As a result, the ring I retainsits sealing ability even if the piston is cocked.

The piston ring, according to the present invention, can be used with anexpander (not shown in the drawings). Such a ring provided with anexpander features a high sealing ability since the flexible bridgesallow the expander to press the ring to, say, the inner surface of thecompressor cylinder (not shown in the drawings).

The piston ring, according to the invention, provided with an expander,functions as a self-sealing element of the piston seal (not shown in thedrawings), similarly to the above-described version. Besides, theexpander presses the outer surface 3 constantly against the wall of thecylinder (not shown in the drawings).

The piston rings made of, say, a fluoroplastic-based material can beused in the stages of the piston compresor without lubricating thecylinder.

The metal piston rings made according to the invention and used withexpanders must be used for the ultrahigh-pressure stages with lubricatedcylinders.

The metal piston ring, according to the invention, made with a presetnominal size of the outer cylindrical surface and preliminarily openedto a preset size for bending and thermal fixing of the flexible bridgeswill possess the requisite flexibility. Such a piston ring must be usedin the highand medium-pressure stages with lubricated cylinders.

What is claimed is:

1. An integral piston ring comprising: an outer surface, an innersurface, and two face surfaces one of which must be directed towards thezone of relatively low pressure of the working fluid while the other onetowards the zone of relatively high pressure; blind slots which open onsaid outer surface and on said face surface directed towards the zone ofrelatively low pressure, a part of the ring between said slots forming aflexible bridge; a slot located between two of said blind slots, madefrom inside of said ring in the zone of said bridge and opening on theouter surface from the side of the face surface which is directedtowards the zone of relatively high pressure; said slot forms a channelfor the passage of the working fluid from the zone of relatively highpressure into the zone of relatively low pressure.

2. An integral piston ring according to claim 1, wherein said channelmade inside of said ring is covered by a circular insert.

1. An integral piston ring comprising: an outer surface, an innersurface, and two face surfaces one of which must be directed towards thezone of relatively low pressure of the working fluid while the otherone - towards the zone of relatively high pressure; blind slots whichopen on said outer surface and on said face surface directed towards thezone of relatively low pressure, a part of the ring between said slotsforming a flexible bridge; a slot located between two of said blindslots, made from inside of said ring in the zone of said bridge andopening on the outer surface from the side of the face surface which isdirected towards the zone of relatively high pressure; said slot forms achannel for the passage of the working fluid from the zone of relativelyhigh pressure into the zone of relatively low pressure.
 2. An integralpiston ring according to claim 1, wherein said channel made inside ofsaid ring is covered by a circular insert.